To research the adaptive evolution and coevolution of the rbcL gene in the genus Galdieria, 36 sequences were selected. The bioinformatics of proteins encoded by rbcL genes of Galdieria were analyzed, and phylogenetic trees were constructed by the maximum likelihood method. Then, adaptive evolution and coevolution were analyzed. The phylogenetic tree showed that the inner groups were clustered into four branches, in which the sequences of Galdieria maxima were divided into two small branches, and the posterior probability of each branch is above 94.9%. Eleven reliable positive selection sites were detected in the branched-site model, indicating that the rbcL protein-coding gene of Galdieria underwent adaptive evolution to adapt to extreme environments. Site 269 F is located in the loop6 domain, while sites 272 D and 273 W are located in the 6-helix structure. Many coevolution pairs were detected, which were closely related to the hydrophobic and molecular weight correlation values of amino acids. The results are helpful to research the evolution process of freshwater red algae, to explore the changes of its essential genes and protein functions to adapt to different environmental pressures, and to understand the close relationship between amino acids in proteins and the molecular mechanism of evolution.

中文翻译：

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红藻属(Rhodophyta) rbc L 基因的适应性进化和协同进化分析

为了研究Galdieria属中rbcL基因的适应性进化和协同进化，选择了36个序列。分析了Galdieria rbcL基因编码的蛋白质的生物信息学，并采用最大似然法构建系统发育树。然后，对适应性进化和协同进化进行了分析。系统发育树显示，内群聚为4个分支，其中Galdieria maxima的序列分为两个小分支，每个分支的后验概率均在94.9%以上。在分支位点模型中检测到 11 个可靠的正选择位点，表明 Galdieria 的 rbcL 蛋白编码基因经历了适应性进化以适应极端环境。Site 269 F位于loop6域，而位点 272 D 和 273 W 位于 6 螺旋结构中。检测到许多共同进化对，它们与氨基酸的疏水性和分子量相关值密切相关。研究结果有助于研究淡水红藻的进化过程，探索其基本基因和蛋白质功能的变化以适应不同环境压力，了解蛋白质中氨基酸与进化分子机制的密切关系。